[Effects of mastication and submandibular gland ectomy on the growth ability of isoproterenol-stimulated parotid gland and other tissues in male mice].

In a previous article we reported that mastication played an important role in the development of submandibular glands in male mice. Submandibular glands contain epidermal growth factor (EGF) which stimulates the proliferation of various cells in developing animals. In this study, the effects of the hypotrophy of submandibular glands caused by reduction of mastication and the removal of the glands on the growth ability of isoproterenol (IPR)-stimulated parotid glands and other tissues were investigated. The animals in the experiment were male mice and they divided into three groups, a control group fed a solid diet, a group fed a paste diet and a group with removed submandibular glands fed a solid diet. In comparison with the group fed a solid diet, in the group fed a paste diet a small decrease was found, and in the group with the ectomized submandibular gland a significant decrease in the rise of ornithine decarboxylase (ODC) activity, S-adenosylmethionine decarboxylase (SAMDC) activity and DNA synthesis of parotid glands caused by IPR stimulation were found. The DNA synthesis of the heart tissue of mice with ectomized submandibular glands was lower than that of the control group, but in liver, lung, stomach and testis tissue no decrease of DNA synthesis was found. These results suggest that mastication and the submandibular glands have an effect of the growth of the tissues in male mice.